An Automated System for Strain Engineering and Straintronics of 2D Materials

This work presents an automated three-point bending apparatus that can be used to study strain engineering and straintronics in 2D materials. This work benchmarks the system by reporting reproducible strain tuned micro-reflectance, Raman, and photoluminescence spectra for monolayer molybdenum disulfide (MoS2). These results are in good agreement with reported literature using conventional bending apparatus. This work further utilizes the system to automate strain investigations of straintronic devices by measuring the piezoresistive effect and the strain effect on photoresponse in an MoS2 electrical device. The details of the construction of the straightforward system are given and it is anticipated that it can be easily implemented for study of strain engineering and straintronics in a wide variety of 2D material systems

The nature of pre-­‐service science teachers’ argumentation in inquiry-­‐oriented laboratory context

The aim of this study was to investigate the kinds of argumentation schemes generated by pre-service elementary science teachers (PSTs) as they perform inquiry-oriented laboratory tasks, and to explore how argumentation schemes vary by task as well as by experimentation and discussion sessions. The model of argumentative and scientific inquiry was used as a design framework in the present study. According to the model, the inquiry of scientific topics was employed by groups of participants through experimentation and critical discussion sessions. The participants of the study were 35 PSTs, who teach middle school science to sixth through eighth grade students after graduation. The data were collected through video- and audio-recordings of the discussions made by PSTs in six inquiry-oriented laboratory sessions. For the analysis of data, pre-determined argumentation schemes by Walton were employed. The results illustrated that PSTs applied varied premises rather than only observations or reliable sources to ground their claims or to argue for a case or an action. It is also worthy of notice that the construction and evaluation of scientific knowledge claims resulted in different numbers and kinds of arguments. Results of this study suggest that designing inquiry-oriented laboratory environments, which are enriched with critical discussion, provides discourse opportunities that can support argumentation. Moreover, PSTs can be encouraged to support and promote argumentation in their future science classrooms if they engage in argumentation integrated instructional strategies

The pedagogy of argumentation in science education: Science teachers’ instructional practices

Argumentation has been a prominent concern in science education research and a common goal in science curriculum in many countries over the past decade. With reference to this goal, policy documents burden responsibilities on science teachers, such as involving students in dialogues and being guides in students’ spoken or written argumentation. Consequently, teachers’ pedagogical practices regarding argumentation gain importance due to their impact on how they incorporate this practice into their classrooms. In this study, therefore, we investigated the instructional strategies adopted by science teachers for their argumentation-based science teaching. Participants were one elementary science teacher, two chemistry teachers, and four graduate students, who have a background in science education. The study took place during a graduate course, which was aimed at developing science teachers’ theory and pedagogy of argumentation. Data sources included the participants’ video-recorded classroom practices, audio-recorded reflections, post-interviews, and participants’ written materials. The findings revealed three typologies of instructional strategies towards argumentation. They are named as Basic Instructional Strategies for Argumentation, Meta-level Instructional ‌St‌‌rategies for ‌Argumentation, and Meta-strategic Instructional ‌St‌‌rategies for ‌Argumentation. In conclusion, the study provided a detailed coding framework for the exploration of science teachers’ instructional practices while they are implementing argumentation-based lessons

The pedagogy of argumentation in science education: Science teachers’ instructional practices

Argumentation has been a prominent concern in science education research and a common goal in science curriculum in many countries over the past decade. With reference to this goal, policy documents burden responsibilities on science teachers, such as involving students in dialogues and being guides in students’ spoken or written argumentation. Consequently, teachers’ pedagogical practices regarding argumentation gain importance due to their impact on how they incorporate this practice into their classrooms. In this study, therefore, we investigated the instructional strategies adopted by science teachers for their argumentation-based science teaching. Participants were one elementary science teacher, two chemistry teachers, and four graduate students, who have a background in science education. The study took place during a graduate course, which was aimed at developing science teachers’ theory and pedagogy of argumentation. Data sources included the participants’ video-recorded classroom practices, audio-recorded reflections, post-interviews, and participants’ written materials. The findings revealed three typologies of instructional strategies towards argumentation. They are named as Basic Instructional Strategies for Argumentation, Meta-level Instructional ‌St‌‌rategies for ‌Argumentation, and Meta-strategic Instructional ‌St‌‌rategies for ‌Argumentation. In conclusion, the study provided a detailed coding framework for the exploration of science teachers’ instructional practices while they are implementing argumentation-based lessons

Structural and magnetic properties of Co-doped Er2O3 nanoparticles

Er-2_xCoxO3 (x=0.00, 0.04, 0.10, 0.30, 0.4) solutions were synthesized by the sol-gel technique using erbium 2,4 pentadionate and cobalt acetylacetonate dissolved in methanol and acetyl acetone. The various obtained Co-doped Er2O3 nanoparticles were annealed at 900 degrees C to hod a doping effect on the structural and magnetic properties. The crystal structures and morphology of the Co-doped Er2O3 nanoparticles were characterized using 2 theta-theta X-ray diffraction (XRD) and scanning electron microscope (SEM). ESR spectra of Er-2_xCoxO3 nanoparticles were collected at room temperature with a Bruker EMX model X-band spectrometer at a frequency of 9.5 GHz. (C) 2014 Elsevier By. All rights reserved